12 research outputs found
Supersymmetric Moduli Stabilization and High-Scale Inflation
We study the back-reaction of moduli fields on the inflaton potential in
generic models of F-term inflation. We derive the moduli corrections as a power
series in the ratio of Hubble scale and modulus mass. The general result is
illustrated with two examples, hybrid inflation and chaotic inflation. We find
that in both cases the decoupling of moduli dynamics and inflation requires
moduli masses close to the scale of grand unification. For smaller moduli
masses the CMB observables are strongly affected.Comment: 5 page
Challenges for Large-Field Inflation and Moduli Stabilization
We analyze the interplay between K\"ahler moduli stabilization and chaotic
inflation in supergravity. While heavy moduli decouple from inflation in the
supersymmetric limit, supersymmetry breaking generically introduces
non-decoupling effects. These lead to inflation driven by a soft mass term,
, where is a supersymmetric mass parameter.
This scenario needs no stabilizer field, but the stability of moduli during
inflation imposes a large supersymmetry breaking scale, , and a
careful choice of initial conditions. This is illustrated in three prominent
examples of moduli stabilization: KKLT stabilization, K\"ahler Uplifting, and
the Large Volume Scenario. Remarkably, all models have a universal effective
inflaton potential which is flattened compared to quadratic inflation. Hence,
they share universal predictions for the CMB observables, in particular a lower
bound on the tensor-to-scalar ratio, .Comment: 44+1 pages, 6 figures, minor modifications, references adde
Large-field inflation and supersymmetry breaking
Large-field inflation is an interesting and predictive scenario. Its
non-trivial embedding in supergravity was intensively studied in the recent
literature, whereas its interplay with supersymmetry breaking has been less
thoroughly investigated. We consider the minimal viable model of chaotic
inflation in supergravity containing a stabilizer field, and add a Polonyi
field. Furthermore, we study two possible extensions of the minimal setup. We
show that there are various constraints: first of all, it is very hard to
couple an O'Raifeartaigh sector with the inflaton sector, the simplest viable
option being to couple them only through gravity. Second, even in the simplest
model the gravitino mass is bounded from above parametrically by the inflaton
mass. Therefore, high-scale supersymmetry breaking is hard to implement in a
chaotic inflation setup. As a separate comment we analyze the simplest chaotic
inflation construction without a stabilizer field, together with a
supersymmetrically stabilized Kahler modulus. Without a modulus, the potential
of such a model is unbounded from below. We show that a heavy modulus cannot
solve this problem.Comment: 19 pages, 3 figures, comments and references adde
No-scale D-term inflation with stabilized moduli
We study the consistency of hybrid inflation and moduli stabilization, using the Kallosh-Linde model as an example for the latter. We find that F-term hybrid inflation is not viable since inflationary trajectories are destabilized by tachyonic modes. On the other hand, D-term hybrid inflation is naturally compatible with moduli stabilization due to the absence of a large superpotential term during the inflationary phase. Our model turns out to be equivalent to superconformal D-term inflation and it therefore successfully accounts for the CMB data in the large-field regime. Supersymmetry breaking can be incorporated via an O'Raifeartaigh model. For GUT-scale inflation one obtains a stringent bound on the gravitino mass. A rough estimate yields m_3/2 \gtrsim 10^5 GeV, contrary to naive expectation
No-scale D-term inflation with stabilized moduli
We study the consistency of hybrid inflation and moduli stabilization, using the Kallosh--Linde model as an example for the latter. We find that F-term hybrid inflation is not viable since inflationary trajectories are destabilized by tachyonic modes. On the other hand, D-term hybrid inflation is naturally compatible with moduli stabilization due to the absence of a large superpotential term during the inflationary phase. Our model turns out to be equivalent to superconformal D-term inflation and it therefore successfully accounts for the CMB data in the large-field regime. Supersymmetry breaking can be incorporated via an O'Raifeartaigh model. For GUT-scale inflation one obtains stringent bounds on the gravitino mass. A rough estimate yields 10^5 GeV \lesssim m_3/2 \lesssim 10^10 GeV, contrary to naive expectation
Large-field inflation and supersymmetry breaking
Large-field inflation is an interesting and predictive scenario. Its non-trivial embedding in supergravity was intensively studied in the recent literature, whereas its interplay with supersymmetry breaking has been less thoroughly investigated. We consider the minimal viable model of chaotic inflation in supergravity containing a stabilizer field, and add a Polonyi field. Furthermore, we study two possible extensions of the minimal setup. We show that there are various constraints: first of all, it is very hard to couple an O'Raifeartaigh sector with the inflaton sector, the simplest viable option being to couple them only through gravity. Second, even in the simplest model the gravitino mass is bounded from above parametrically by the inflaton mass. Therefore, high-scale supersymmetry breaking is hard to implement in a chaotic inflation setup. As a separate comment we analyze the simplest chaotic inflation construction without a stabilizer field, together with a supersymmetrically stabilized Kahler modulus. Without a modulus, the potential of such a model is unbounded from below. We show that a heavy modulus cannot solve this problem